Monchausen

Hello, first sorry for the translation since I am Spanish, I am restoring a 928 S4 from 1990, the car has been stopped for more than 10 years, we have made the engine, I just painted it, I am missing the interior, the car I think has all the symptoms that the control unit is broken, the gasoline pump does not work, it does work if I make the bridge on the relay, I turn on the ignition and a click sounds in the engine, it seems that it is the idle valve, it starts with the pump turned on, but it does not hold the idle, it does not exceed 1000/1500 rpm and stops in 20-30 seconds, it smells a lot of badly burned gasoline. I do not know where to start, I have bought the cold start sensor, I still have not been able to put it, but how can I make sure that it is or is not the ECU? What steps should I take?
I have found a website that sells the board that is changed to the ECU, or so I think https://www.sacer-shop.com/sa1093.html I do not know if someone has been able to test it, or better send it to JDS.

Thank you very much

FredR

The EZK [ignition control unit] rarely fails. If a computer has failed it will likely be the LH unit and one of the classic signs of failure is fuel injectors clicking and the engine going nowhere- you could send the unit to John in the UK[ [url]http://jdsporsche.com ] who will test it for a small fee and repair it if needs be. The main sign of LH failure is the fuel pump not working.

The CPS [crank position sensor] also has to be viable- checking that is somewhat more involved so no point in getting ahead of ourselves at the moment and the Mass Airflwo sensor [MAF] also needs to be viable- the engine can run with that item down but it will not run properly.

The sensor you are talking about is likely the temp2 sensor- this tells the computers what temperature the engine is at and makes adjustments in the settings as appropriate for the prevailing conditions.

Have you changed out the gasoline? -i.e. has that been stagnating or did you empty the tank and fill with fresh gasoline?

worf928

What Fred wrote. Your symptoms are consistent with, amoung others, LH ECU failure.

There is at least one other Rennlister from Spain. If he’s close by he might be able to test your LH in his 928.

If not, send it to JDS.

Monchausen

The gasoline is completely new, as well as the pump, filters, seals, oils. I think the best thing would be to send the switchboard, thanks and I'll tell you how it went.